The jewlwery box was first introduced as an item of interest in episode 7 of the series "Long Live the Mayor". It belonged to Skylar Stephens's parents, and is seen in multiple episodes of the series (in Skylars house, at parties). It is particularly interesting for three reasons.

1) It is a family heirloom.

2) It is empty.

3) It appears in places it does not belong (including Jonston Green's office in episode 10).

The third example can mean either that the prop was misplaced as a production error, or that there was actually significance since it is shown in multiple locations that Skylar never even appears in the show.